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Discussion Starter #1
Sportwagon 156 JTD 2.4 2001.

Thought it might be useful to have a check list - to narrow down possibilities of whats wrong.

Symptoms are:

Blower works fine, hot air fine, but no cold air. All aircon lights are working. I do NOT hear the revs dip when I press the aircon button - although I have read the compressor wont activate if there is no gas.

I've had the gas check - and although not totally full, the guy told me is was OK.

What else could / should I check?

Fuse - if so where is it.

Compressor? If this the alternator size thing driven by a belt off the engine.

Electric pump - is there one? And how to check...

Anything else?


I'm on a budget - sigh:( :(


cheers all:)
 

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Sportwagon 156 JTD 2.4 2001.

Thought it might be useful to have a check list - to narrow down possibilities of whats wrong.

Symptoms are:

Blower works fine, hot air fine, but no cold air. All aircon lights are working. I do NOT hear the revs dip when I press the aircon button - although I have read the compressor wont activate if there is no gas.

I've had the gas check - and although not totally full, the guy told me is was OK.

What else could / should I check?

Fuse - if so where is it.

Compressor? If this the alternator size thing driven by a belt off the engine.

Electric pump - is there one? And how to check...

Anything else?


I'm on a budget - sigh:( :(


cheers all:)
Looking into mine at the moment - yep, the compressor is about the size of an alternator and driven off a belt. You can tell which it is by the metail aircon pipes going into it. To see if it's engaging, check the metal disc at the end of the pulley - when you press the A/C button, it should start spinning indicating it has received power. Things that would stop the compressor engaging:
Pressure sensor telling ECU not enough pressure in system
Bad fuse not supplying power
Broken compressor clutch
Bad A/C relay

There's another thread somewhere on this forum which has a good link to a youtube video showing common diagnostic steps to take when looking at faulty aircon.
 

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If the system pressure is too high or too low, the ECU will not engage the A/C compressor.
 

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Discussion Starter #4
Johnnygal - just the sort of response I was hoping for, thanks. Those metal discs you mention - do you mean they are on the end of the compressor shaft?

Pressure sensor telling ECU not enough pressure in system - Where is it and how do you test?

Bad fuse not supplying power - Power to what? And where is the fuse, I can't seem to find one. Is it inside the cabin with the other fuses?

Broken compressor clutch - again where and how to check / fix


Bad A/C relay -- This I found, the contacts were fairy corroded and fuzy. I gave it a good clean and oil, but it still doesn't work.

David C - thanks also. The chap at Halfords had a guage that said " Full", " Alert ", and "Empty". It was on the upper part of Alert ( near the Full zone ).
 

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Johnnygal - just the sort of response I was hoping for, thanks. Those metal discs you mention - do you mean they are on the end of the compressor shaft?

Pressure sensor telling ECU not enough pressure in system - Where is it and how do you test?

Bad fuse not supplying power - Power to what? And where is the fuse, I can't seem to find one. Is it inside the cabin with the other fuses?

Broken compressor clutch - again where and how to check / fix


Bad A/C relay -- This I found, the contacts were fairy corroded and fuzy. I gave it a good clean and oil, but it still doesn't work.

David C - thanks also. The chap at Halfords had a guage that said " Full", " Alert ", and "Empty". It was on the upper part of Alert ( near the Full zone ).
Yep, you can make out a metal disc and nut on the end of the compressor shaft at the belt end.

I meant the Climate Control fuse (Fuse number 9 in my manual) but this would probably takeout all the Climate Control and not the A/C.

URL to youtube video - not an Alfa but covers aspects of the aircon system.
YouTube - Saturn S-series A/C Troubleshooting(part 1)of 2
Basically you need to start at the compressor and work backwards, as per video
 

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Discussion Starter #9
Hmmmm...now heres a thing.

I had a brainwave - as in I currently have two Sportwagons:D

My old black 2.0 156 TS 2001 ( soon to be sold )

And my new Silver JTD ( with non-working Aircon )

So first I took the A/C relay from the old car to the new one - no change, so the relays are fine.

Now I looked and looked on the JTD compressor - but couldn't find the disk you were referring to:confused: :confused:

When I looked on the TS - there is was large as life - motionless with aircon off, spinning when I switched it on.

So where is it on the JTD? When I look there is a pulley on the compressor - but where the central disk is on the TS - there is nothing!! Please dont tell me it fell off!!!:wow:
 

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Daytona, what year is your JTD. Mine is 2005 and while the metal plate doesn't stick right out, you can see the edge of it enough to notice that it's spinning or not. Maybe dab a bit of tippex on the end nut to make it easier to see if spinning or not. You should also hear a loud click when the A/C button is pressed when the compressor clutch engages.
 

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Discussion Starter #11
Mines a 2001 JTD,

Definitely no click when I press the button.

The pulley on the compressor has a void where the metal disk should be - I can only imagine there never was a clutch there - but if not then where.....?

What about the pressure switch sensor - where is that? Could be something else to check?
 

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I only mention the disc as an easy way to see if your compressor is truning. The fact you cannot hear a click suggests it isn't.

I'm not sure whereabouts the pressure sensor is, suggest tracking all metal pipes to find it.

Maybe get a multimeter on the compressor to see if it's getting any juice.
 

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Hi Daytona

I had fun and games with my A/C and it turned out to be an electrical fault on a connector block up above the glovebox.

Also you mention that the Halfords guage showed 'Nearly full' Don't be fooled by this - If the compressor is not running you will only get a standing pressure reading which will be higher than normal. It could be that you simply don't have enough refridgerant in there.

You could do worse than taking it to Kwik Fit as they will re-gas for £45 and if they can't get it colder than when you went in it's free. That's what I did just to rule out whether it had gas or not (They didn't charge me a bean as they couldn't get it working).

However in the end my woes were solved by calling in a local A/C expert (Drivecool in Norwich) and I must say it was money well spent for his diagnostic skills.

Hope you get it sorted.
 

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You have to remove the glovebox and the bit of carpet above where your feet would be and the connector is up there somewhere. I didn't actually do it myself but was there when the mechanic did it.

By a process of elimination (using wiring diagrams) he found the wire in the engine bay which controls the compressor engagement and followed it back until he found the bad connection. It's all been fine since then (touch wood).

I would check all the simple things first though before you go taking things apart (i.e. refridgerant, relays, fuses etc.). I had exactly the same thing when I initially took mine to Halfords - the fella put his gauge on and it said 'Danger - Do not add refridgerant'. This was because the compressor wasn't working so the reading was high. Actually i had the right amount in there.

Kwik fit will put the car on a more sophisticated machine but at the end of the day they are not air-con experts so if it's anything more than a simple re-gas they won't be able to help you (although they probably won't charge you either and at least you'll know if your system has the right amount of gas).

As for you pics I must admit I haven't seen a compressor like that (mine is the one with the protruding metal clutch). I have heard that some manufacturers use compressors which run all the time and use other parts of the system to cut in and out but I didn't know ALFA used them.

I think the ALFA compressors are made by SANDEN (see here for list of parts and pics of different compressors they make for ALFA's http://www.eclima.com/ITALIAN/ALFA ROMEO.pdf) and it could just be that the clutch mechanism is recessed on yours so it's not so obvious.

Anyway if it's working you should hear a pretty loud click when you press the A/C button and the revs will dip a bit. If you don't hear it engage then it could be a gas or electrical problem.
 

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Discussion Starter #16
Right - bear in mind the problem is that there is no 'click' sound when I push the aircon button - indicating that the aircon compressor clutch is not being activated.

Well, did a bit more checking, and these are the results:

I bypassed the relay as per this thread ( last post ).

http://www.alfaowner.com/Forum/alfa-147-156-and-gt/36464-the-air-con-compressor-story-when-its-cold-outside.html

No results.

I then tested the power supply to the compressor ( clutch )...and I got a steady 14 volts....as shown in this Youtube aircon diagnostic clip.

YouTube - Saturn S-series A/C Troubleshooting(part 1)of 2

I then ran a lead straight from the positive battery terminal and dabbed it on the compressor clutch connector. Again, no click sound.


So is this a buggered compressor? Where can I get a working second hand one from -- Alfa quoted me £309 for a reconditioned one:wow:

And also what I need to know is are they all the same through the 156 range - so would a 156 TS compressor work on the JTD.

Finally, bearing in mind its a belt slackening job -- is it a DIY job?

cheers all
 

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Discussion Starter #17
OK - I took it to Halfords...and they drained the coolant with no problems, did a leak test ( no leaks ), put oil in, and with the engine running, put gas in.

But there was a problem with putting the gas in, as the gas going in was entering the system very very slowly, and got up to only 145g ( out of 500g required )*. The technician was quite helpful, but couldn't explain why it wouldn't fill.

Said it may be the compressor at fault, which was what I was hoping not to hear. But it occured to me that surely with the pressure switch the compressor wouldn't come on until it was at the correct pressure?

What would cause it not to take gas?



* It may have gone higher - but he reckoned we'd be there til midnight!
 

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Was he filling up the correct side? There's a high and low pressure connection and using the wrong one will take ages. Apparently Renaults only have one large connector and if they had been switched before your Alfa and not switched back ....
 

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When I first got mine the aircon wasn't cold. I just put up with it for a couple of weeks thinking it was just the way it was, until I wanted to use the cigarette lighter - wasn't working either.

Put in a new fuse - sorted. Can light my rollups and lovely icy aircon !
 
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